1. Field of the Invention
The present invention relates to novel acylmethylene-1,3-dioxolanes and acylmethylene-1,4-dioxanes, and to a novel process for their preparation.
Acylmethylene-1,3-dioxolanes and acylmethylene-1,4-dioxanes are important intermediates for the preparation of pyrazoles and anthranilamides, which can be used as insecticides.
2. Description of the Related Art
The literature has already described how certain dioxolane derivatives in the presence of acid anhydrides have a tendency towards spontaneous polymerization (Spontaneous co-polymerization of 4-methylene-1,3-dioxolanes with maleic anhydride, Fukuda, Hiroyuki; Hirota, Masahiro; Nakashima, Yoshihiro, Nagoya Munic. Ind. Res. Inst., Rokuban, Japan, Journal of Polymer Science, Polymer Chemistry Edition (1982), 20 (6), 1401-9.) The acylmethylene-1,3-dioxolanes and acylmethylene-1,4-dioxanes according to the invention, however, are not described; a process for their preparation is not described in the literature either.
It was therefore an object to provide a process which allows acylmethylene-1,3-dioxolanes and acylmethylene-1,4-dioxanes to be prepared in a simple manner without the disadvantages described in the prior art and on an industrial scale from known 4-methylene-1,3-dioxolanes and 6-methylene-1,4-dioxanes.